Which statement about hydrant grid systems is true?

• A. They generally have higher friction loss and deterioration
• B. They generally have less friction loss and deterioration
• C. They have unpredictable friction loss
• D. They require more frequent maintenance

Answer: (B)

Hydrant grid systems distribute water through an interconnected network of mains, forming multiple parallel paths to any hydrant. This setup lets the fire-flow demand be shared among several routes rather than pushed through a single long feed.

Friction loss is tied to how much water is flowing through each pipe and how long that flow travels. When the system splits the flow across multiple shorter segments, each segment carries a lower flow rate and experiences less velocity, which reduces the friction losses in those pipes. The overall effect is a lower total head loss for delivering water to the same hydrant compared to a single, dominant feed.

The redundancy of a grid means no one pipe is routinely carrying the entire load. That reduces stress and wear on any given segment, which helps limit deterioration and simplifies maintenance because problems can be isolated and addressed without compromising the entire network. This combination of reduced friction loss and slower deterioration makes hydrant grid systems advantageous for reliable firefighting water supply.